Alloplasmic male sterility in Brassica napus (CMS 'Tournefortii-Stiewe') is associated with a special gene arrangement around a novel atp9 gene
Alloplasmic male sterility in Brassica napus (CMS 'Tournefortii-Stiewe') is associated with a special gene arrangement around a novel atp9 gene
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DOI：
10.1007/s00438-003-0886-3
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发表时间：
2003-08-01
影响因子：
3.1
通讯作者：
Schmitz, UK
中科院分区：
文献类型：
--
作者：
Dieterich, JH;Braun, HP;Schmitz, UK
为了确定可能参与甘蓝型油菜同种异体tourneforti - stiewe细胞质雄性不育（CMS）表达的线粒体基因组区域，分析了可育和近等基因雄性不育植物（BC8代）的25个线粒体基因的转录本。ATP合成酶（atp9）亚基9、细胞色素b （cob）亚基和NADH脱氢酶（nad2）亚基2基因的转录存在差异。这些基因区域的结构分析揭示了雄性不育和可育植物之间围绕atp9的基因组组织的差异。在CMS植物的线粒体中存在三个atp9基因，其中两个迄今为止尚不为人所知，其中一个基因的上游重排产生了一个嵌合的193密码子ORF，命名为orf193。该区域转录为CMS特异性双顺反子mRNA，全长1.58 kb，由orf193和atp9组成。异常的1.58 kb转录本水平在通过尚未表征的核基因恢复育性的植物中降低。orf193编码一个22.7 kDa的多肽，其部分序列与ATP合成酶复合物的亚基6一致。然而，由于它与新发现的atp9基因之一形成不间断的ORF，它也可能被翻译为嵌合的30.2 kda蛋白。可能是其中一个或两个基因产物干扰了线粒体F0F1-ATP合成酶的功能或组装，从而损害了高度依赖atp的花粉发育过程。本文讨论了异源性“Tournefortii-Stiewe”CMS的新分子特征以及其他已知的甘蓝型油菜CMS机制。
To identify regions of the mitochondrial genome potentially involved in the expression of alloplasmic 'Tournefortii-Stiewe' cytoplasmic male sterility (CMS) in Brassica napus, transcripts of 25 mitochondrial genes were analysed in fertile and near isogenic male-sterile plants (BC8 generation). Differences were detected in the transcription of genes for subunit 9 of ATP synthase (atp9), cytochrome b (cob) and subunit 2 of NADH dehydrogenase (nad2). Structural analysis of these gene regions revealed differences in genome organisation around atp9 between male-sterile and fertile plants. Three atp9 genes, two of which were hitherto unknown, are present in the mitochondria of CMS plants, and rearrangements upstream of one of these genes have generated a chimeric 193-codon ORF, designated orf193. This region is transcribed as a CMS specific bi-cistronic mRNA of 1.58 kb comprising orf193 and atp9. The level of the aberrant 1.58-kb transcript is reduced in plants restored to fertility by as yet uncharacterized nuclear genes. orf193 encodes a polypeptide of 22.7 kDa which exhibits partial sequence identity to the subunit 6 of the ATP synthase complex. However, as it forms an uninterrupted ORF with one of the newly discovered atp9 genes it may also be translated as a chimeric 30.2-kDa protein. It is likely that either or both gene products interfere with the function or assembly of the mitochondrial F0F1-ATP synthase, thus impairing the highly ATP-dependent process of pollen development. The novel molecular features of alloplasmic 'Tournefortii-Stiewe' CMS are discussed with respect to the other known mechanisms of CMS in B. napus.